WASHINGTON (Reuters) - A U.S. federal appeals court is expected to rule by Dec. 6 whether to uphold a law requiring Chinese-based ByteDance to divest its popular short video app TikTok in the U.S. by early next year or face a ban.

President-elect Donald Trump has said he will not allow TikTok, which is used by 170 million Americans, to be banned.

Below are several scenarios on how a three-judge panel of the U.S. Court of Appeals for the District of Columbia could rule.

The District of Columbia Appeals Court typically issues rulings on Tuesdays and Fridays.

COURT UPHOLDS THE LAW

Circuit Judges Sri Srinivasan, Neomi Rao and Douglas Ginsburg are currently considering the legal challenges brought by TikTok and users against the law that gives ByteDance until Jan. 19 to sell or divest TikTok's U.S. assets or face a ban.

The court could rule to uphold the law, validating the U.S. government's position and likely compelling TikTok to quickly appeal the ruling to the Supreme Court or to the full District of Columbia circuit.

COURT UPHOLDS THE LAW BUT SAYS IT IS UNFAIR TO TIKTOK

The Justice Department says TikTok under Chinese ownership poses a serious national security threat because of its access to vast personal data of Americans, asserting China can covertly manipulate information that Americans consume via TikTok.

The Court could rule to uphold the law, but also say it is unfair the legislation expressly singles out ByteDance and TikTok under the Constitution's prohibition of "Bills of Attainder" - laws that directly impose a punishment on a specific person, entity or class. The court could direct the U.S. government follow a process to potentially certify that TikTok is a national security threat, giving the app a lifeline or a significant delay in a possible ban.

COURT RULES LAW IS UNCONSTITUTIONAL

The court could agree with TikTok and ByteDance, who argue the law is unconstitutional and violates Americans' free speech rights. They call it "a radical departure from this country's tradition of championing an open Internet." The Justice Department could appeal to the Supreme Court or full appeals court panel.

(Reporting by Chris Sanders and David Shepardson)